Apparatus for making basic furnace linings and bottoms



Sept. 2, 1947. w, SDEBENHAM 2,426,673

APPARATUS FOR MAKING FURNACE LININGS AND BOTTOMS Original Filed April 27, 1945 2 Sheets-Sheet l INVENTOR W/ZA/AMJ DEBE/VHAM,

Sept, 2, 1947. w. s. DEBENHAM 2,426,673

' APPARATUS FOR MAKING BAsIc FURNACE LININGS Am) BOTTOMS Original Filed April 27, 1945 2 Sheets-Sheet 2 l E l .l

iV/z Z/AMJ y- Patented Sept. 2, 1947 APPARATUS FOR MAKING BASKC FURNACE LININGS AND EOTTGMS William S. Debenham, Chicago, HlL, assignor to Carnegie-Ellinois Steel Gorporation, a corporation of New Jersey Original application April 27, 1945, Serial No. 590,634. Divided and this application February 26, 1946, Serial No. 650,176

2 Claims.

This invention relates to apparatus for making basic furnace linings and bottoms, and more particularly, the linings and bottoms in furnaces such as basic open hearth furnaces and electric furnaces with basic linings.

The invention has among its objects the provision of a novel compacting or ramming apparatus for operating upon the'furnace bottom or lining material in carrying out certain steps of the method of making basic linings or bottoms for furnaces disclosed in application Serial No. 590,634, filediApril 27, 1945, of which this application is a division.

This and further object of the invention will be more readily apparent in the following description.

The apparatus of the present invention is applicable to and displays advantages in the making of linings or bottoms in various types of furnaces employing basic materials for such purpose, such as open hearth furnaces and electric furnaces, where the lining or bottom material is applied in granular form and is sintered in place. For the purposes of illustration, however, the invention will be particularly described in connection with the making of a bottom in a basic open hearth furnace wherein its advantages are particularly great.

The invention will be mor readily understood by reference to the accompanyin drawings, in which:

Figure 1 is a view in transverse vertical sec tion through a typical basic open hearth furnace;

Figure 2 is a view in longitudinal vertical section through a portion of such furnace, said section being taken along the line IIII in Figure 1;

Figure 3 is a View in front elevation of a furnace bottom ramming or pressing device made in accordance with the present invention;

Figure 4 is a view in section throughthe presser shown in Figure 3, such section being taken along the line IVIV in Figure 3; and

Figure 5 is a view in vertical section through such presser, the section being taken along the line VV in Figure 4.

The open hearth furnace 2 which is shown in Figures 1 and 2 provides a covered hearth in the form of a large shallow receptacle in which the charge of metal is placed, such charge then being subjected to the action of flames directed over the top thereof alternately from either end of the furnace for the purpose of melting the charge to allow its purification and the addition of desired amounts of alloying ingredients. As a, re-

sult of the high temperature to which the furnace is subjected, the linin is eroded by the bath, becoming progressively thinner in successive heats, and therefore frequentl must be renewed.

As shown in Figures 1 and. 2, furnace Z is provided with a foundation l of insulation and/or fireclay brick, a layer of basic brick 6, usually chrome or chrome-magnesite brick, on top of such foundation, and a bottom 8, which, in a basic open hearth furnace, is composed largely ofmagnesite grain sintered in place ontop of the basic brick, It is with the application of the furnace bottom 8, whether in a new furnace or in an old furnace upon relining thereof, with which the present invention is concerned. Bottom 8 includes beside that part of the lining actually in contact with the bath the curved front banks It shown in Figure 1 leading up to the charging doors Q2 of the furnace and the inclinedrear- Ward portion A l which is termed the backwall.

My aforesaid copending application describes and claims a method for preparing furnace bot-. toms wherein a layer of granular'refraotory material is applied to the furnace bottom, the furnace is heated to sintering temperature, and pres sure is applied to the bottom material to compact it and provide a bottom of the desired configuration. The present invention relates to apparatus particularly suited for applying pressure to the bottom material in preparing furnace bottoms according to this method.

The presser device of the present invention consists of a curved form l8, preferably made of cast iron, such form being roughly of a shape corresponding to half a right circular cylinder. One portion of the curved surface thereof, the front surface 2! may be made of circular cylindrical contour, but the rear curved surface 22 thereof, although it may be circular in cross sectional shape, is preferably made of a longer radius than the front portion so that it conforms more closely to the surface of the backwall of the furnace. The presser is also. provided with two end walls 24 and 23 whichcomplete the structure.

Such presser, which is of considerable weight and which may be weighted still further if desired by the placing of weights therein, is conveniently manipulated by means of the ram of the charging machine with which every open hearth and any electric furnace of appreciable size is equipped. The ram I6, shown in Figures 1 and 2 with the presser mounted thereon, is provided at its forward end with a conventional flange-type mounting and locking means which is used for engaging the conventional chargin boxes of the furnace. In order to make the presser adaptable to the different contours of the furnace bottom, it is provided on the front end V the presser having cooperating recessed portions and a centrally located hole therethrough for the vertical reception of the flange 29 on the outer end of the charging machine ram and the slidable locking pin 3| through ram I6, respecor three such complete pressings of the entire furnace bottom area, additional layers of magnesite about four inches thick being shoveled onto the furnace bottom between successive pressing operations. In some instances, it is necessary in order to reach areas behind the door jambs or to press the curved boundary areas pf the furnace bottom, to present. the presser in varying relationships to the furnace bottom. This can be tively. Socket 30 on the end of the presser is similarly formed, with the exception that the,

plate 32 on the inner surface of the wall 2| contains only one recess for the reception of the flange on the ram.

It will be readily apparent that with the four sockets by which the presser may be mounted on the ram, the ram, which as is well-known, may be adjusted angularly in a vertical plane, may be adjusted longitudinally of the furnace, may be projected into the furnace through the charg ing door to variable extents, and may be rotated about its own axis, can present the form to the furnace bottom in such manner that the entire area of the bottom which may be reached through the charging doors can be covered and shaped to the desired contour.

In lining a basic open hearth furnace, the hearth foundation is prepared in the usual manner and the grain'm'agnesite, which is preferably straight grain magnesite of fine particle size containing over 80% MgO is shoveled over the bot-v tom and burned as in making a regular burnedin bottom. When the bottom has been built up to a depth of approximately six inches and has attained a surface temperature of approximately 2900 F. or above, the fuel is shut off and the presser member quickly inserted by the charging machine through a charging door of the furnace, pushed against the backwall, dra ged across the bottom, rolled against the ends, and pulled against the front banks, thereby pressing down the'bottom and'conforming itto the desired :shape. Usually for commercial magnesite containing 80% MgO and heated to 2900 F. a pressure of ten pounds per square inch between the presser and furnace bottom has been found adequate.

Manipulation of the presser through one furnace door to cover the area of the furnace bottom which can be reached through that door ordinarily requiresone or two minutes. Such period of time is insufficient to heat the presser sufiiciently to damage it. fThe presser is then withdrawn, and the furnace is again heated for onehalf hour to bring the bottom back to temperature, after which the same pressin operation is repeated from the next furnace door and so on until the whole bottom has been consolidated in 76 this manner. Usually it is preferred to use two readily done as above described, either by rotating the ram of the charging machine, as shown in Figure 2, to make the presser conform to the area engaged or in some cases to withdraw the presser from the furnace, place it on a suitable support and to engage it at a different socket by the charging machine ram. Such operation may be quickly and easily accomplished and does not need entail undue cooling of the furnace bottom.

Although the presser has been described as merely being dragged over the furnace bottom, the charging machine upon which it is mounted makes possible, if desired, a tamping action by raising and lowering the ram. 7

It is obvious that variations are possible in the apparatus disclosed, and it is to be understood, therefore, that the scope of the invention is not limited to the disclosed embodiments thereof but is defined by the following claims.

I claim: a r

1. A device for pressing and shaping furnace bottoms comprising a shell having a curved pressing surface andflat upstanding end walls defining substantially a half cylinder, said pressing surface having portions of two different radii of curvature, the upper edge of the portion of smaller radius having a central socket and a similar socket at each side of said central socket, and one of said end Walls having a similar socket, whereby a handle can be selectively engaged with any of said sockets for applying the pressing surface to various regions of'a furnace bottom.

2. A device for pressing and shaping furnace bottoms comprising ashell having a curved pressing surface and flat upstanding end walls defining substantially a half cylinder, said pressing surface having portions of two different radii'of I curvature, the upper edge of the portion of small- 7 er radius having central fastening means and similar fastening means at each side of said cen-' tral, fastening means, and one of said end walls having similar fastening means, whereby a handle can be selectively engaged with'any of said fastening means for applying the pressin surface-to 'various regions of a furnace bottom.

, -WILLIAM S. DEBENHAM.

REFERENCES CITED The following references are of record in the file r this patent; a .7

UNITED STATES PATENTS 7 Vincent Oct. 29; 1929 

